Hydraulic control valve and system



May 26, 1953 R. s. MlLLER ETAL 2,639,693

HYDRAULIC CONTROL VALVE AND SYSTEM Filed April 25, 1949 s SheefcS-Sheet 1 ATTORNEYS '3 Sheets-Sheet 2 IN VEN TOR! @mmw at MIMI! May 26, 1953 R. s. MILLER ETIAL HYDRAULIC CONTROL VALVE AND SYSTEM Filed April 25, 1949 Patented May 26, 1953 HYDRAULIC CONTROL VALVE AND SYSTEM Raymond S. Miller, Hollywood, and George'W. Sinclair, Los Angeles, Calif., assignors to M. 0. Johnston, Glendale, Calif.

Application April 23, 1949, Serial No. 89,321

Claims.

This invention relates to an hydraulic control system and to valve structures useful therein;

It is an object of the invention to provide an improved hydraulic control system and valve structures useful therein.

It is a further object of the invention toprovide an hydraulic control system for controlling an hydraulic cylinder and synchronizing the same with the operation of a pump in order to hoist a load, hold the same and to lower the same at a predetermined rate.

It is a still further object of the invention to provide an hydraulic control system which is adapted to handle large volumes of liquid and to operate cat cylinders and the like used in hoisting, holding and lowering loads and in doing other odd jobs about an oil well drilling rig.

It is yet another object of the invention to provide hydraulically balanced valves which are adapted to use in a control system of the character described.

These and other objects of the invention will be apparent from the ensuing description and the appended claims.\

One form which the invention may assume is exemplified in the following description and illustrated by way of example in the accompanying drawings in which:

' Fig. 1 is a view in longitudinal section of the inlet control valve of the system.

Fig. 2 is a similar view of an outlet control valve taken as a section along the line 2-2 of Fig. 1.

Fig. 3 is a schematic view of the system as a whole, including the valves of Figs. 1 and 2 as parts thereof. l

Referring now to Fig. 1, there is shown an inlet valve structure generally designated as I9 having an inlet Illa and which is formed at one end with a valve seat I I seating a check valve I2. A casting I3 defines a chamber I4, having an outlet passage I5 which communicates-with a cat cylinder or other hydraulic device (not shown) through a gooseneck I5a. and with an outlet control valve 50 which is [described in detail hereinafter.

"he valve I2 has a hollow stem I6 defining a axial passage Ill, and it is slidable in a sleeve 18 in which the hollow rod I9 of a piston is also sli'dably disposed. The rod I9 defines an axial passage IIu. which is in'effect an'extension of the passage H. An enlarged portion formed in passages I1 and Ha receives an expansion spring 26. The piston 20- is held in predetermined position by means hereinafter described,

passage 55.

, 2 and it will be seen that the valve I2 is capable of functioning as a check valve.

The. piston 20 is reciprocable in a chamber 21, and it is formed with a chamber 28, a forward passage 29 and a rearward passage 30. The passages 29 and 30 communicate with the cham'- ber 28 and the latter communicates with the passage I'Ia, as illustrated. A pilot valve 3| is disposed in the chamber 28, and it is provided with a stem 32 which is reciprocable in the pas sage I'Ia. The piston 20 is also formed with valve seats 33 and 34 for the pilot valve 3|. f

It will be apparent that, if the valve 3| is seated on seat 34, inlet pressure will be communicated through passages I1 and I'Ia, chamber 28 and forward passage 29 to chamber 27. Since the area of piston 20 is greater than the area of valve I2, the valve I2 will be positively closed by the pressure in chamber 21 acting on piston 20. When, however, the pilot valve 3| is seated on valve seat 33, pressure in the chamber 21 will bleed through passages 29 and 30 to a chamber 40 and out through a vent line 4| toa sump or storage vessel (not shown). Check valve I2 is then free to open under pressure in the inlet I011. The pilot valve 3| is controlled by an hydraulic slave piston 42, which is reciprocable in a cylinder 43.- Two passages 44 and 45 are formed in the walls of the cylinder 43 and communicate with opposite ends of-the cylinders. Also illustrated is an air bleed passage 46 which is normally sealed by a plug 41. Pressure is delivered to one end or the other of the slave piston through passage '44 or 45, by means described hereinafter. It is apparent that, by actuating piston 42, the pilot valve 3| is actuated and valve I2 is positively closed or is allowed to open under inlet pressure in the valve inlet I0, and that the degree of opening, hence the hydraulic pressure delivered to the hydraulic device; is thereby controlled. It is also apparent that, when the inlet pressure is decreased, spring 26 will close valve I2 to prevent reverse flow of fluid through inlet Ilia. That is, valve I2 serves as a check valve as well as an inlet control valve.

Referring now to Fig. 2, an outlet valve struc ture generally designated as 50 is illustrated. This valve structure-is formed with a valve seat 5| seating a. valve 52. Fluid enters through outlet .passage I5 of inlet control valve I0 into a chamber 54 and passes out through an outlet The valve 52 is provided with a hollow stem 56 which is reciprocable in a sleeve 5'! fixed ,to a casting 58 which defines achamber 59'. A piston 59a is fixed to the other end of the stem 56 and is reciprocable in the chamber 59.

The piston 59a is formed with an inlet passage 60 and an outlet passage BI. The inlet passage, as illustrated, communicates with the left-hand or inboard end of the chamber 59 and, through a dash pct 62 and a passage 63, with the valve chamber 54. The outlet passage 6!, as illustrated, communicates with the chamber 59 and with anaxial passage 54 defined by the hollow stem 56, and through the passage 64, with the outlet 55.

The areas on the opposite side of the piston 59a are equal. Hence, normally this position has no tendency to actuate the valve 52, which is closed by pressure in the chamber .55. FQr the purpose of positively opening the valve 52, 'a pilot valve 16 is provided, which may seat on a valve seat I! to close outlet passage BI, or on a valve seat I2 to close inlet passage 55. Obviously, if the pilot valve It is seated on valve seat 'II, the valve 52 will remain closed, and if valve 'lll is seated on valve seat 12', pressure will bleed from chamber 59 through passages! and 64 to outlet 55. The area of piston 59a is greater than the area of valve 52; hence, when the pressure in chamber 59 is sufiiciently reduced, the valve 52 will be opened by pressure exerted on piston 55a.

The pilot valve Ill is actuated by a slave piston I3 which is reciprocable in a cylinder 14. A rod 15; Connects the pilot valve Ill and slave piston 73, Passages I6 and TI communicate with opposite ends of the piston 13. Also illustrated is an air bleed passage I8 which is normally sealed by a plug 19. Hydraulic fluid under pressure is supplied to one end or the other of the slave piston I3 through passage IE or 'I'I in the manner described hereinafter.

Referring now to Fig. 3, an engine 85 operates a pump 35 throu h any suitable mechanical linkage designated as 8'1. lhe pump 86 operates an hydraulic device 88 to lift a load 94 or to, do other useful work. The hydraulic device 88. is illustrated as comprising a cylinder 83 in which a piston 98 is reciprocable. The piston 91] is con-v nected by a rod SI and a cable 92 trained over a sheave 9 3 to a load Bil. Fluid pressure from the pump is admitted to one side of the piston, 90 through a line 95, and compressed air from any suitable source (not shown) is admittedto the opposite side of the piston 90 through a line 95. The working fluid is the hydraulic fluid entering thro gh 1 1 A. valve control mechanism generally designated as Ifill is illustrated. This control n echap comprises a. housing IBI and it alsooomprises the inlet valve structure ID of Fig. 1 and the outlet valve structure 50 of Fig. 2. Only so much of these valve structures are shown in Fig. 3 as is necessary to understand their functions and. operation. The structure of the control system of Fig. 3 will be best understood by a description of its operation.

If it is desired to, lift the load 94, a remote control lever I52 fulcrumed at I63 is moved to the left, as viewed in Fig. 3. This actuates a lever I04; fulcrumed at I65 and urges a slave piston IBB to the left. The slave piston I06 is reciprocable in a cylinder I Il'I which communicates through lines I08 and I09 with a cylinder H in which a slave piston III is reciprocable. The slave piston II I is connected with a linkage I..I2 with the throttle N3 of the engine 85. Therefore, movement ofthe piston I to the right will obviouslycause movementof' the slave piston I I I to the left and, as illustrated, will'open the throttleIIB- of the engine 85, thus accelerat- 4 ing the engine and thereby accelerating the pump 86 and delivering greater pressure to the hydraulic piston 90 for the purpose of lifting a load. Obviously, the degree of acceleration of the engine 85 and of the pump 86 will be governed by the extent of movement of the control lever I02. Atthe sam time, the control lever I62, acting through a link I20, moves a master piston [2| to the left. The piston I2I is reciprocable in a master cylinder I22. Pressure is thereby transmitted through a line I23 and inlet passage 44 of cylinder 43 to move slave piston 42 up (as v viewed in Fig. 3) and, through the medium of pilot valve 3! etc. (collectively indicated as I24 in Fig. 3) to open valve I2. Pressure from the pump 86 is delivered through a line I25 through inlet passage Illa, past valve I2, and through outlet passage I5 and line 95 to cylinder 89.

At the same time, pressure will be delivered through passage I! to the upper end of cylinder I4 to depress piston I3 and thereby hold outlet valve 52 in closed position through the medium of rod I5, pilot valve Ill, etc. (collectively designated as I26 in Fig. 3).

If it is desired to hold the load at rest, the lever I02 is moved back to vertical or neutral position, Throttle control lever I04 is urged to the right by a spring I27 and is stopped in vertical position by a stop member I28. Engine throttle H3 is thereby returned to idling position so that the engine continues in operation at idling speed and delivers no power to the pump. The tendency of the load 94, will, of course, be to raise the piston 98 and thereby drain hydraulic fiuid from the cylinder 88 back into the pump. This, however, is prevented by the check valve I2,

When it is desired to lower the load, the com trol lever I92 is moved to the right, causing pressure to be delivered through a line I29 and passage A5 to cylinder 43 above piston 42 (thus firmly holding check valve 12 in closed position) and through passage 16 to cylinder I4 below piston I3, thus causing valve 52 to open. Fluid will then drain from cylinder 89 through line 95, pastvalve 52 and through outlet passage 55 and a line I30 to a sump I35. A line I32 communicates sump I3I with pump 35, as illustrated. It will be apparent that the rate of lowering the load can be controlled by lever I 02.

It will thus be apparent that an hydraulic control system and valves useful thereinhave been provided, which are operable to supply hydraulic fluid to an hydraulic cylinder or otherhydraulic device for performing useful work. It will also be apparent that by manipulation of a single. control lever it is possible to supply hydraulic fluid to an hydraulic, cylinder to lift a load at any desired rate, to hold the loadsteady at selected-position, and to lower the load at a controlled rate.

While we have shown the preferred iorm of our invention, it is to; be understood that various changes may be made in its construction. by those skilled in. the art without departing from the spirit of the invention as defined-in. the ap-. pended claims.

Having thus described our invention,.Wl1atWe claim and, desire tc secureby Letters Patent is:

1. An, hydraulic control system. comprising. a floating inlet valve spring pressed toward closed position and being operable as a check valve to prevent return of fluid when pressure on the out.- let side. thereof exceeds pressure on the inlet sid an outlet valve normally closed by outlet pres, sure, 'means for controlling the opening of said inlet valve, means for opening said outlet valve and means for synchronizing said inlet valve and outlet valve control means operable to maintain said outlet valve closed while pressure is being delivered through said inlet valve and to close said inlet valve when pressure is relieved through said outlet valve.

2. An hydraulic control system comprising inlet valve means including a floating inlet valve spring pressed toward closed position so as to tend to open under inlet pressure and to close when the return pressure exceeds the inlet pressure, outlet valve means including an outlet valve tending to close under outlet pressure, hydraulic means for controlling said inlet valve, hydraulic means for opening said outlet valve, and means for synchronizing said hydraulic means to maintain said outlet valve closed while pressure is being delivered through said inlet valve and to close said inlet valve when pressure is relieved through said outlet valve.

3. An hydraulic control system comprising means for supplying hydraulic fluid under pressure, a floating inlet valve operable to pass hydraulic fluid under pressure to an hydraulic device, said inlet valve being spring pressed toward closed position so as to be operable as a check valve to prevent return flow of fluid when the pressure on its outlet side exceeds the pressure on its inlet side, an outlet valve which is normally closed by outlet pressure, and hydraulic means operable to regulate the degree of opening of said inlet valve under inlet pressure, to maintain said outlet valve closed during delivery of inlet pressure, to control the degree of opening of said outlet valve to drain fluid from said hydraulic device and to close said inlet valve when fluid is drained through said outlet valve.

4. An hydraulic control system comprising an inlet valve, a piston movable relative to the inlet valve and being operable to close said inlet valve and to control the degree of opening thereof under inlet pressure, means for communicating inlet pressure to said piston to operate the same, a pilot valve operable to control the pressure on said piston, an outlet valve, a piston operable to close the same and to control the degree of opening thereof, means for communicating outlet pressure to said piston to operate the same, a pilot valve operable to control the pressure on said piston, and hydraulic means for operating said pilot valves.

5. An hydraulic control system comprising an inlet valve, a piston movable relative to the inlet valve and being operable to close said inlet valve and to control the degree of opening thereof under inlet pressure, means for communicating inlet pressure to said piston to operate the same, a pilot valve operable to control the pressure on said piston, an outlet valve, 3, piston operable to close the same and to control the degree of opening thereof, means for communicating outlet pressure to said piston to operate the same, a pilot valve operable to control the pressure on said piston, and hydraulic means for operating said pilot valve, said hydraulic means being operable to maintain said outlet valve closed while pressure is being delivered through said inlet valve and to close said inlet valve when pressure is being relieved through said outlet valve.

RAYMOND S. MILLER. GEORGE W. SINCLAIR.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 344,307 Crouan June 22, 1886 354,020 Morey Dec. 7, 1886 396,206 Heermans Jan. 15, 1889 412,327 Gibson Oct. 8, 1889 531,595 Otis Dec. 25, 1894 560,230 Powers, Jr May 19, 1896 1,012,004 Pearson Dec. 19, 1911 1,165,653 Dunn Dec. 28, 1915 1,214,496 Armstrong Feb. 6, 1917 1,764,366 Stuebing June 17, 1930 2,038,167 Farmer et al. Apr. 21, 1936 2,146,213 Horton Feb. 7, 1939 2,417,947 Reedy Mar. 25, 1947 

